A lot of people would see it that way. But in most instances that is a fallacious belief; the content will reappear on an exam.
EDIT:
cont. above:
Also, remember this work is not only for an exam, you will benefit from actually knowing it. Rather than waiting till it is "over".
Yeah, there is the dodgy method of helping your class after the SAC, in order to secure first ranking. Assuming they perform better in the exam, that would give you a major advantage.
I just realised this is incorrect; if first ranking is obtained you are only dependent, at least in theory, on the best exam performance. Anything other than first ranking is influenced by the entire cohort.
But as I said already: try your best, you'll get what you deserve. Also, don't be afraid to help, it can only advance yourself; both intellectually and numerically(ATAR etc...). Remember: don't make this year
only about score; there is so much more than that to life.